Calculating Toolface

Projecting AheadProjecting Ahead If we superimpose the current well path onto the planned well path, a triangle forms as illustrated below. We can calculate the change necessary to achieve desired inclination and azimuth. 4000 4050 4100 KOP East -50 0 50 100 300 True Vertical Depth 4150 4200 4250 4300 4350 4400 4450 4400 4450 4400 4450 -50 0 50 100 150 200 250 Legend Well Plan Actual 100 0 -100 N W Target at 25° Azimuth View from Southeast of Rig Vertical Section on 25.00 azimuth View down from Rig Floor Figure 1 Projecting ahead USDDSM04B June 3, 1998 © Copyright 1998, Sperry-Sun, a division of Dresser Industries, Inc. North 200 1 Determine the number of degrees change in the hole direction. a division of Dresser Industries. Convert the polar coordinates to rectangular coordinates using the ∆ direction from step #1 and the desired inclination. so the difference between azimuths is 25o 2. ∆ Direction = (Azimuth 1 .25). Sperry-Sun.Calculating the Toolface Setting to Project Ahead Calculating the Toolface Setting to Project Ahead Current: Inclination Azimuth Inclination Azimuth = 6o = 0o (N00E) = 8o = 25o (N25E) Desired: 1. Inc. 1998 . USDDSM04B June 3.Azimuth 2) ∆ Direction = (0 . Y) D re esi dI ina ncl tion Y D Direction X X = cos(D Direction) x Desired Inclination(Hypotenuse) Y = sin(D Direction) x Desired Inclination(Hypotenuse) Figure 2 Conversion of coordinates from polar to rectangular 2 © Copyright 1998. Polar Coordinates = Desired Inclination at D Direction Rectangular Coordinates = (X. 25 . Inc.6.38 D Direction = 25° X = 7.Calculating the Toolface Setting to Project Ahead Polar Coordinates = Desired Inclination at D Direction Rectangular Coordinates = (X.6.25 Figure 4 Determining the new x value USDDSM04B June 3.0 = 7.Current Inclination = New X Value X .0 = 1. Subtract the current inclination from the X value. Y) s De In ired clin n atio =8 Y = 3.25 X = cos(D Direction) x Desired Inclination(Hypotenuse) Y = sin(D Direction) x Desired Inclination(Hypotenuse) Figure 3 Computation of rectangular angle coordinates from change in direction/desired inclination 3. 3 . Sperry-Sun. a division of Dresser Industries. 1998 © Copyright 1998.25 X .38 25° X = 1. 8 3. 38/1. 1998 .7° Figure 6 Determining new toolface setting a c B = 1.69.704) a = 69. Create a new triangle from the new set of rectangular coordinates. Inc.38 25° X = 1.25 and Y = 3.38 8 y = 3. Sperry-Sun.Calculating the Toolface Setting to Project Ahead 4.25 Figure 5 Creating a new triangle 5.25 Note: a + b = 90° b = 90 .38 25° a = atan(A/B) a = atan(3. Convert the rectangular coordinates of the new triangle back to polar coordinates A( Y) by using the following formula: C = atan ----------B(X) b 8 C=? A = 3.3° 4 © Copyright 1998.a b = 90 . a division of Dresser Industries.7 = 20. USDDSM04B June 3.25) a = atan(2. X = 1. Y = 3. Inc.7° 60 8 25° 6 7.Calculating the Toolface Setting to Project Ahead C = A2 + B2 C = 3.5625 C = 12. use the standard dogleg calculation.382 + 1. 8 3. a division of Dresser Industries. Note: DL = acos ( cos I 1 × cos I 2 ) + ( sin I1 × sin I 2 × cos ∆ AZ ) = 3. In situations where inclination angles are 30o or greater.25 Calculate the length of the triangle’s hypotenuse.60 Figure 7 Determining dogleg (hypotenuse) 6.60373 = 3.60 C= a 69.7° b A = 3.25 X= 1. This formula provides acceptable dogleg values for inclinations of less than 30o.4244 + 1. 1998 © Copyright 1998.25 Figure 8 Completed dogleg calculations USDDSM04B June 3.38 5 . Sperry-Sun.252 25° C = 11.9869 C = 3.38 c B = 1. or for projecting ahead calculations. Dog leg 69. Example: 3. USDDSM04B June 3. Sperry-Sun. a division of Dresser Industries. 100 are the measuring units (substitute 30 if working in meters). DD is the given distance in which the directional driller desires the change to be achieved.Calculating the Toolface Setting to Project Ahead The dogleg from our toolface calculation can be used to calculate the amount of hole that needs to be drilled to accomplish the change. 1998 . DL • 100 DLS = --------------------DD where: DL is the calculated dogleg DLS is the dogleg severity created if the change takes place over a given distance. Inc. You use the following formula: DL • 100 DD = --------------------DLS MAX where: DL is the calculated dogleg. Example: 3. if the change is made over a given distance. DD is the drilled distance required to make the change.6 • 100 72 ft = --------------------5° The calculated dogleg may also be used to calculate the dogleg severity of the change. DLSMAX is the maximum acceptable dogleg for this portion of the hole.6 • 100 4 degrees / 100 DLS = --------------------90 ft 6 © Copyright 1998. build rate).e. 1998 © Copyright 1998. Sperry-Sun.5°/100 = 3.0 Percentage Footage Oriented = 66.67 Percentage Footage Oriented = 67%. DLO is the Actual Dogleg while drilling oriented °/100. USDDSM04B June 3. 7 .0 ) × 100 Percentage Footage Oriented = -------------------------3. Inc.5 – 0. a division of Dresser Industries.5°/100 ( 2.5 – 0. DLR is the Actual Dogleg while drilling rotary °/100.0 200 Percentage Footage Oriented = -------3.Calculating the Toolface Setting to Project Ahead During the Build Section. ( DL – DLR ) × 100 Percentage Footage Oriented = --------------------------------------------DLO – DLR Where: Planned Build Rate Build Rate while Oriented Build Rate while Rotary = 2.5°/100 = 0. what percent of the footage will be drilling oriented? Where: DL is the Required Dogleg °/100 (i.5 ) × 100 Percentage Footage Oriented = ---------------------------------------3.5 ( 2. Inc. 4. What is the Dogleg for the motor? What is the Change in Direction? What is the Inclination at the Bit? What is the Azimuth at the Bit? 8 © Copyright 1998. 1998 . use the following formula: Dogleg × sin Toolface Set C = atan -------------------------------------------------------------------A + ( Dogleg × cos Toolface ) To calculate the new inclination. a division of Dresser Industries.1 feet) with a toolface setting of 20L. 3. Sperry-Sun. use the following formula: Dogleg C MAX = asin -------------------------------------------Present Inclination Example 1 Current Depth = 2000 Current Inclination = 6. USDDSM04B June 3.0° You drill 2 joints (62. use the following formula: Dogleg × sin Toolface Set B = -------------------------------------------------------------------------------sin Expected Change In Direction To calculate the new inclination.0° Current Azimuth = 48. What is the Inclination and Azimuth at the bit if the motor dogleg is expected to be 5°/100? 1. 2.Calculating the Toolface Setting to Project Ahead Where: A = Inclination at Survey 1 B = Inclination @ Survey 2 C = Change in Direction To calculate the expected change in direction. 105 2.061973 Bit Inc = --------------------0.105 × cos 20 ) 1.118231 Bit Inc = 8. What is the Azimuth at the Bit? Azimuth At Bit = Current Azimuth – Change In Azimuth Azimuth At Bit = 48 – 6.79 Azimuth At Bit = 41.105 × sin 20 Change In Direction = atan -----------------------------------------------6 + ( 3.061973 Change In Direction = atan --------------------8. Sperry-Sun. What is the Inclination at the Bit? Dogleg × sin Toolface Set Bit Inc = -------------------------------------------------------------------------------sin Expected Change In Direction 3.98 ° 4.× 62.79 1. Inc. a division of Dresser Industries.1 Dogleg = -------100 Dogleg = 3.× Distance Drilled Dogleg = ----------------------100 5° .Calculating the Toolface Setting to Project Ahead 1. What is the Change in Direction? Dogleg × sin Toolface Set Change In Direction = atan -------------------------------------------------------------------------------------------Current Inc + ( Dogleg × cos Toolface ) 3. 1998 © Copyright 1998.79 ° 3.917746 Change In Direction = 6. 9 .2 ° USDDSM04B June 3.105 × sin 20 Bit Inc = -------------------------------sin 6. What is the Dogleg for the motor? DL Motor ° . 5 100 Dogleg = 2. 2.052991 Change In Direction = atan --------------------6.3 ) 1. Inc.× Distance Drilled Dogleg = ----------------------100 3 °Dogleg = -------× 92. 4. What is the Dogleg for the motor? What is the Change in Direction? What is the Inclination at the Bit? What is the Azimuth at the Bit? 1.5 feet) with a toolface setting of 45 (Magnetic Toolface).1 + ( 2. a division of Dresser Industries.3 Change In Direction = atan --------------------------------------------------------4.3 = 22. USDDSM04B June 3.97 ° 10 © Copyright 1998. What is the Inclination and Azimuth at the bit if the motor dogleg is expected to be 3°/100? 1.3 L Dogleg × sin Toolface Set Change In Direction = atan -------------------------------------------------------------------------------------------Current Inc + ( Dogleg × cos Toolface ) 2. 1998 . What is the Change in Direction? (Find Toolface first) Toolface = Magnetic Toolface Setting – Current Azimuth Toolface = 45 – 67.667457 Change In Direction = 8.Calculating the Toolface Setting to Project Ahead Example 2 Current Depth = 2000 Current Inclination = 4.775 × cos 22.3 = – 22. 3. Sperry-Sun.3° You drill 3 joints (92.1° Current Azimuth = 67. What is the Dogleg for the motor? DL Motor ° .775 2.775 × sin 22. What is the Azimuth at the Bit? Azimuth At Bit = Current Azimuth – Change In Azimuth Azimuth At Bit = 67.75 ° 4.3 Bit Inc = ------------------------------------sin 8.Calculating the Toolface Setting to Project Ahead 3.155917 Bit Inc = 6.33 ° USDDSM04B June 3.97 1. 11 . What is the Inclination at the Bit? Dogleg × sin Toolface Set Bit Inc = -------------------------------------------------------------------------------sin Expected Change In Direction 2. Sperry-Sun. a division of Dresser Industries. Inc. 1998 © Copyright 1998.052991 Bit Inc = --------------------0.775 × sin 22.3 – 8.97 Azimuth At Bit = 58. Sperry-Sun. a division of Dresser Industries. 1998 .Calculating the Toolface Setting to Project Ahead 12 © Copyright 1998. USDDSM04B June 3. Inc.